Just wondering if this is a decent carb for a '77 305? This'll be a reman'd carb that I caan get for $75. Any input you guys can give a newbie?

Thanks,
Andrew

No.

I got a 4 bbl 600cfm edelbrock and matching intake manifold off a board member here for that price. Closed loop would seem to indicate that it is meant to be run with a computer system?

<font face="Arial,Verdana" size="2">Originally posted by Skaal-tel 79:
Closed loop would seem to indicate that it is meant to be run with a computer system?</font>

Yep.

I have found 2 good 750 and 2 good 800 Rochs from the wreckers mainly from 77-86 Chev GM pick ups. ( the lower the vintage, the more likely the right kind. 80-81s are for certain the good ones ) They are 17 bucks apiece where I "shop" ;-). There are 100s of them, mostly grunge covered burnt out junk but every now and then you find a very nice clean newish one or recently rebuilt one.

They are M4Ms, have round chokes attached to the bodies. They don't have that little cup/plug affair on top like 80s car and all later trucks with M4MEs have. Ther are plenty of pics of them in manuals, magazines and on the net. The ones with the long "noses" inside the primaries are 800s ( climb up in the truck, open the choke and look, the smaller round "noses" are 750s ). Double check by looking in the primary venturies deeper to see which is which. The 750s also have a noticable little "ring/bulge" around them half way down the primary. The 800 has a clearly bigger primary venturi bore and a small bulge in it.

M4MEs are not good material for hot rodding. For a 305, likely a 750 would be best ( I got a gem from a 77 Malibu wagon with a 305 ). They are "demand" carbs on the secondaries and theoretically give your engine only what it wants so they can't be "too big". Smaller primaries on the 750 I think would make for a better vaccum signal for a small 305.

If your going Roch, act quickly, if you are considering having a selection of jets and rods around. They are drying up. Great carbs IMHO.

Look for Q-Jets from the late-60s and early-70s, try Ebay, or post on the Swap Meet section. You'll be much better off with a carb of this vintage.

Your 77 doesn't have the computer and related sensors necessary to run that carb properly. Without the computer doing it's job it'll default to full-rich and run like a pig.

An earlier 74-up NON computer controlled QJet with the integral choke built into the side of the carb would be what you want. Just make sure you get the CHEVY style of QJet (fuel inlet points to the side) to assure compatibility with your current throttle and tranny cables.

I don't usually debate folks here but I agree with Damon ( an easy choice to make ;-) and would ask Sharpeyewashington to clarify his notion that the older ones are better. I've had them both apart and they are identical from a performance and tuning standpoint. I would agree the earlier ones are just as good but I can't see how they would be better.

The only issues I have with the earlier ones are parts availablity is even tougher and the choke is a bigger problem to set up with most manifolds. The later ones Damon refers too are absolutely every bit as easy a carb to tune up and rework as the ealier ones. There is a way better supply of simple "kits" available. As I noted I see no basic differance other than the newer ones are easier to get.

Q-jets are so plentiful that you should be able to find an earlier version that would run better, stronger and more reliable.

The M4ME's were notorious for leaking and running rich. Most of the problems came from the idle mixture solinoid that would cause enrichment problems over and beyond the usual main well leaks.

It is almost impossible to over carburate a Chevy small block with a properly functioning Q-jet as the carb delivers only what the motor needs. Q-jets are set-it and forget-it where as Holleys are forever requiring tuning. The Edelbrock / Carter AFB carbs are also good carbs but a good Q-jet will out-perform them if set-up right!

If you're looking for Q-jet tunning parts like metering rods and jets, they are availible from Edelbrock in kits or individually and can be ordered from Summit or Jegs.

Dump the M4ME and find an earlier non-electronic carb.

Kamikazee, the word at the local auto parts speed shops is Edlebrock is dropping it and ordering individual parts is about a 1 in 3 chance of the part actually exsisting. I'll try Jegs and Summit myself since you mentioned it but Edlebrock is apparantly drying up.

camertom;

Edelbrock is clearing house on a lot of items.

The Q-jet program has been overshadowed by Performer series (AFB) carbs and the newer thunder series, (AVS) carbs. They are clearing out for newer items but you can still get most of the stuff if you deal with someone who's willing to order it for you. Summit & Jeg's are usually pretty good when you have manufacturers part numbers.

Get yourself a 2005 Edelbrock catalog or better yet, you can download it for free from their website so you can order by part numbers.

One item that I've had problems finding was a thermostatic choke coil that mounts on the passenger side of the manifold for early seventies GM. NAPA, Car Quest, and the other parts store don't list them but Edelbrock was the only one to have these brand new! If you have a 68-74 GM car, you might want to snatch this up before they go away!

A couple of other sources for Q-Jet parts are:

Sean Murphy Induction systems, (SMI) and the Carb Shop. I bought many items from the Carb shop when Brad Urban was still alive but I don't know if they are still in Ontario, CA.

SMI has been advertising in the back of Super Chevy and other magazines.

OK, so if I went to AutoZone, what do you guys suggest I get. I'd like to get something new, so if anyone could give me a specific model that'd be great. I also have an Edelbrock Performer 2101 to hook up. This is tough for me because I'm better with computers than I am with engines. Hopefully by the time I'm done with this, I'll have a nice set up for myself that I can talk intellegently about. I'd rather get in there and do it myself as much as I can- makes me feel more like a classic sports car owner than a classic sports car driver. http://www.nastyz28.com/ubb/biggrin.gif

Since you're working with a 305, and I'm assuming no other mods, (cam, heads, exhaust), then the best thing for you would be to get a #1400 Performer Carb. It a 600 cfm with an electric choke and easy to set-up & maintain. This should be more than enought to give you good performance and driveability without over-carbing or flooding out your engine. It is also a good starting point if you ever build up that 305 or even a healthy 350!

Check around on prices as I've seen some reall good deals on this model on the net too!

Alot of people have suggested a 750 carb, what would be the difference between the two?

You could use the 750 but unless you have the compression, cam, cylinder head flow, exhaust, ignition, etc, etc, you're just going to "over-carb" that little 305! Your engine might be able to use it but not to it's full advantage!

Don't fall into the " Bigger is better" syndrome! The smaller 600 cfm will give you better throttle response, better fuel mileage and better performance overall.

but bigger is better... hhhhhhhhhhhmmmm... OK, Edelbrock 600 electric choke-

going once...

I just bought this one on E-bay for my 305 in my 80.
It came off of an 80 Vette. The last year before the comp-controlled carb.
http://i16.ebayimg.com/01/i/04/16/c7/e7_1_b.JPG

It took me a while to find an 80 carb with the electric choke intact. (Now... where did I hide that choke wire?)

I'm gonna clean it up, drop it in and see if it runs better than my old Q-jet which has no choke and hasn't been rebuilt in 20 years.

If it needs rebuilding, I'll swap back and rebuild this one.

[This message has been edited by Twisted_Metal (edited August 10, 2005).]